Tomographic reconstruction of a CME from three and two viewpoints. (a) Ground-truth electron density slices in the ecliptic plane and at 135°longitude; the blue dashed lines indicate the locations of the latitudinal slices. (b) Reconstructed slices from a three-viewpoint configuration and corresponding difference maps relative to the ground truth. (c) The same as panel (b), but for a two-viewpoint reconstruction. The comparison highlights that the CME morphology can be reconstructed with a high degree of fidelity even from a sparse set of observations.